/*
 * Copyright 2012-2018 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package cn.springcloud.gray.bean.convert;

import org.springframework.core.convert.ConversionService;
import org.springframework.core.convert.converter.ConverterRegistry;
import org.springframework.core.convert.support.ConfigurableConversionService;
import org.springframework.core.convert.support.DefaultConversionService;
import org.springframework.format.FormatterRegistry;
import org.springframework.format.support.DefaultFormattingConversionService;
import org.springframework.format.support.FormattingConversionService;
import org.springframework.util.StringValueResolver;

/**
 * A specialization of {@link FormattingConversionService} configured by default with
 * converters and formatters appropriate for most Spring Boot applications.
 * <p>
 * Designed for direct instantiation but also exposes the static
 * {@link #addApplicationConverters} and
 * {@link #addApplicationFormatters(FormatterRegistry)} utility methods for ad-hoc use
 * against registry instance.
 *
 * @author Phillip Webb
 * @since 2.0.0
 */
public class ApplicationConversionService extends FormattingConversionService {

    private static volatile ApplicationConversionService sharedInstance;

    public ApplicationConversionService() {
        this(null);
    }

    public ApplicationConversionService(StringValueResolver embeddedValueResolver) {
        if (embeddedValueResolver != null) {
            setEmbeddedValueResolver(embeddedValueResolver);
        }
        configure(this);
    }

    /**
     * Return a shared default application {@code ConversionService} instance, lazily
     * building it once needed.
     * <p>
     * Note: This method actually returns an {@link ApplicationConversionService}
     * instance. However, the {@code ConversionService} signature has been preserved for
     * binary compatibility.
     *
     * @return the shared {@code ApplicationConversionService} instance (never
     * {@code null})
     */
    public static ConversionService getSharedInstance() {
        ApplicationConversionService sharedInstance = ApplicationConversionService.sharedInstance;
        if (sharedInstance == null) {
            synchronized (ApplicationConversionService.class) {
                sharedInstance = ApplicationConversionService.sharedInstance;
                if (sharedInstance == null) {
                    sharedInstance = new ApplicationConversionService();
                    ApplicationConversionService.sharedInstance = sharedInstance;
                }
            }
        }
        return sharedInstance;
    }

    /**
     * Configure the given {@link FormatterRegistry} with formatters and converters
     * appropriate for most Spring Boot applications.
     *
     * @param registry the registry of converters to add to (must also be castable to
     *                 ConversionService, e.g. being a {@link ConfigurableConversionService})
     * @throws ClassCastException if the given FormatterRegistry could not be cast to a
     *                            ConversionService
     */
    public static void configure(FormatterRegistry registry) {
        DefaultConversionService.addDefaultConverters(registry);
        DefaultFormattingConversionService.addDefaultFormatters(registry);
        addApplicationFormatters(registry);
        addApplicationConverters(registry);
    }

    /**
     * Add converters useful for most Spring Boot applications.
     *
     * @param registry the registry of converters to add to (must also be castable to
     *                 ConversionService, e.g. being a {@link ConfigurableConversionService})
     * @throws ClassCastException if the given ConverterRegistry could not be cast to a
     *                            ConversionService
     */
    public static void addApplicationConverters(ConverterRegistry registry) {
        addDelimitedStringConverters(registry);
        registry.addConverter(new StringToDurationConverter());
        registry.addConverter(new DurationToStringConverter());
        registry.addConverter(new NumberToDurationConverter());
        registry.addConverter(new DurationToNumberConverter());
        registry.addConverter(new StringToDataSizeConverter());
        registry.addConverter(new NumberToDataSizeConverter());
        registry.addConverterFactory(new StringToEnumIgnoringCaseConverterFactory());
    }

    /**
     * Add converters to support delimited strings.
     *
     * @param registry the registry of converters to add to (must also be castable to
     *                 ConversionService, e.g. being a {@link ConfigurableConversionService})
     * @throws ClassCastException if the given ConverterRegistry could not be cast to a
     *                            ConversionService
     */
    public static void addDelimitedStringConverters(ConverterRegistry registry) {
        ConversionService service = (ConversionService) registry;
        registry.addConverter(new ArrayToDelimitedStringConverter(service));
        registry.addConverter(new CollectionToDelimitedStringConverter(service));
        registry.addConverter(new DelimitedStringToArrayConverter(service));
        registry.addConverter(new DelimitedStringToCollectionConverter(service));
    }

    /**
     * Add formatters useful for most Spring Boot applications.
     *
     * @param registry the service to register default formatters with
     */
    public static void addApplicationFormatters(FormatterRegistry registry) {
        registry.addFormatter(new CharArrayFormatter());
        registry.addFormatter(new InetAddressFormatter());
        registry.addFormatter(new IsoOffsetFormatter());
    }

}
